<!DOCTYPE html>
<html>

<head>
	<meta charset="UTF-8" />
	<title>Document</title>
</head>

<body>
	<script type="text/javascript">
		class Person {}
		Person.prototype.b = 200

		class Student extends Person {
			name = 'tom'
		}
		Student.prototype.a = 100 //a想给s用

		const s = new Student()

		console.log(s.b)
	</script>
</body>

</html>